At present most television broadcasting, regardless of medium over which the signal is broadcast (Terrestrial, Cable, Satellite), is analogue based and comprises a single television service (e.g. SKY ONE, SKY SPORTS, SKY MOVIES) transmitted on a carrier signal or channel. However, the use of digital based broadcast technology is imminent. Digital broadcast technology will enable television service companies to transmit in a single channel high definition television programmes, or plural programmes at conventional definition or multiple customer services, or a combination of these.
In a conventional analogue-based television broadcast system programmes (or “services”) are broadcast by separate television service companies on a single carrier signal (“channel”). In a digital based broadcast system it is possible to broadcast plural services multiplexed together on a single carrier. Unless the context requires otherwise the term “channel” will be used herein to refer to the bandwidth used by a single service to broadcast television programmes or other customer services. The term “channel” therefore encompasses both an entire carrier signal (when the signal is used entirely by a single service) and a portion of a carrier signal (when the signal is shared by plural services).
The ability to transmit multiple channels in a single carrier signal enables a far greater number of services to be provided in the digital domain than is possible in the analogue domain. Some of the channels in a carrier may be used to provide conventional television programmes while simultaneously other channels in the carrier are used to provide data for other customer services such as television programme listings, on-line programme ordering or so-called pay-per-view (PPV) services, and so on. Customer services should not be confused with the “services” provided by television companies as discussed hereinabove.
In our International (PCT) patent application published as WO 96/37996, the teachings of which are incorporated herein by reference, there is disclosed a receiver for television signals, which receiver is arranged to receive video signals comprising video data, information data and audio signals comprising audio data and information data. The receiver is arranged to respond to viewer operation of a control device. The receiver includes a processor for processing selected information data to convert the same into signals representative thereof for output to a television in combination with the video signals. In one mode of operation the decoder responds to manipulation of the control device by causing brief scheduling information pertaining to programmes of a plurality of different TV signals to be displayed over the received signal. In another mode of operation the receiver is arranged to display detailed scheduling information pertaining to plural different television signals. The receiver is operable to receive signals containing video data representing a plurality of video clips. The processor is arranged to process the signals and to cause simultaneous display of the clips on a television screen. The processor is arranged to respond to user manipulation of the control device by storing data for subsequent viewing of user selected programmes. The decoder may further comprise a modem and various types of digital storage media including Hard Disk, CD-ROM drive, Digital Video Disk.
In addition to such television related services some of the channels in a carrier may be used to provide on-line shopping facilities by which a customer may purchase goods and/or services from their own home. Such on-line shopping is, of course, only possible if there is an element of interaction between the goods/service provider and the customer. The term “interactive services” will be used herein to refer generally to on-line shopping facilities and the like made available via one or more channels in a digital based broadcast system.
Digital data multiplexing techniques enable a single channel to carry simultaneously multiple interactive services. In itself this creates a problem. Many customers will find bewildering the large number of interactive services available to them. If customers become confused they will not make use of the interactive services. Clearly, this is undesirable.
Transmission bandwidth is a finite resource and will remain at a premium even if full advantage is taken of digital data compression techniques. This presents a problem when it comes to providing an interactive service. On the one hand it is desirable to present high quality pictures and graphics. However, higher quality necessitates the use of a larger bandwidth. On the other hand it is desirable to keep costs down because customers will not make use of interactive services if they are significantly more expensive than comparable high street services.
In our International (PCT) patent application published as WO 97/23997, the teachings of which are incorporated herein by reference, there is disclosed a receiver for television signals, which receiver is arranged to receive video signals comprising video data and information data. The receiver is arranged to respond to viewer operation of a control device. The receiver includes a processor for processing selected information data to convert the same into signals representative thereof for output to a television in combination with the video signals. The receiver is arranged to respond to the information data to output for display data derived from said image data and said information data and representing an inter-active image. The receiver is responsive to viewer manipulation of the control device to vary the inter-active image and to establish a telecommunications link to a remote site for on-line interaction via the inter-active image between the viewer and the remote site. The interactive image may form part of an interactive services interface comprising a broadcast entry level and plural broadcast interactive levels. The inter-active services interface may comprise one or more on-line interactive levels entered from one of the broadcast interactive levels for establishing an on-line connection with a remote site.